CHAPTER II.

MIRACULOUS VESSELS OF THE GREEKS. THE DICAIOMETER. Heron, in his “Pneumatics,” describes a large number of wonderful vessels that were used by the ancients, and, among them, one called the “dicaiometer” (a correct measure), which allowed of the escape of but a definite quantity of the liquid that it contained. [Illustration: THE DICAIOMETER.] This was constructed as follows: Let us suppose a vessel (see the illustration) whose neck is closed by a diaphragm. Near the bottom there is placed a small sphere, Τ, of a capacity equal to the quantity that it is desired to pour out. Through the diaphragm there passes a small tube, Δ Ε, which communicates with the small sphere. This tube contains a very small aperture, Δ, near and beneath the diaphragm. The sphere contains at its lower part a small aperture, Ζ, whence starts a tube, Ζ Η, that communicates with the hollow handle of the ewer. Alongside of this aperture the globe contains another one, Λ, through which it communicates with the interior of the ewer. The handle is provided with a vent, Θ. After closing the latter, the ewer is filled with liquid through an aperture that is afterwards stopped up. The tube, Δ Ε, may likewise be made use of, but in this case it is necessary to form a small aperture in the body of the ewer in order to allow the air to make its exit. The globe, Τ, fills at the same time that the ewer does. Now, if we turn the ewer over, leaving the vent Θ open, the liquid in the globe, Τ, and in the small tube, Δ Ε, will flow out. If we close the vent and bring the ewer to its former position, the globe and the tube will fill up anew, since the air that they contain will be expelled by the liquid that enters thereinto. The ewer being again turned over, an equal quantity of liquid will flow anew, save a difference due to the small tube, Δ Ε, since this latter will not always be full, and will empty in measure as the ewer does; but such difference is very insignificant. MIRACULOUS VESSELS. Ctesias, the Greek, who was physician to the Court of Persia at the beginning of the fourth century of our era, and who has written a history of that country, narrates the following fact: Xerxes, having caused the tomb of Belus to be opened, found the body of the Assyrian monarch in a glass coffin which was nearly full of oil. “Woe to him,” said an inscription at the side, “who, having violated this tomb, does not at once finish the filling of the coffin.” Xerxes, therefore, at once gave orders to have oil poured into it; but whatever the quantity was that was put in, the coffin could not be filled. This miracle must have been effected by means of a siphon, analogous to the one found in the Tantalus cup, and which becomes primed as soon as the level rises in the vessel above the horizontal; that is, on a line with the upper part of the tube’s curve. In fact, proof has been found of the use of the siphon among the Egyptians as far back as the eighteenth dynasty, and Heron, in his “Pneumatics” (book xii., chap. iii.), describes a very large number of vessels that are founded upon its use. The ancients, likewise, solved a problem contrary to that of the tomb of Belus, and that was one connected with the construction of a vessel that should always remain full, whatever was the quantity of water that was removed from it, or, at least, which should remain full even when a large quantity of water was taken from it. The annexed engraving (Fig. 1) shows one of the arrangements employed. [Illustration: FIG. 1.--A MIRACULOUS VESSEL OF HERON.] “Let Α Β be a vessel containing a quantity of water equal to that which may be demanded, and Γ Δ a tube that puts it in communication with a reservoir, Η Θ, lower down. Near this tube there is fixed a lever, Ε Ζ, from whose extremity, Ε, is suspended a cork float, Κ, and to whose other extremity, Ζ, there is hooked a chain that carries a leaden weight, Ξ. “The whole should be so arranged that the cork, Κ, which floats on the water, shall close the tube’s orifice; that when the water flows out, the cork, in falling, shall leave such aperture free; and, finally, that when a new supply of water enters, the cork shall rise with it and close the orifice anew. To effect this the cork must be heavier than the leaden weight suspended at Ξ. Now, let Λ Μ be a vessel whose edges should be at the same height as the level of the water in the reservoir when there is no flow through the tube because of the cork float. Again, let Θ Ν be a tube that connects the reservoir with the base of the vessel, Λ Μ. [Illustration: FIG. 2.--MIRACULOUS VESSEL OF HERON.] “So, then, when we remove water from the vessel, Λ Μ, after it has once been filled, we shall at the same time lower the level of the water in the reservoir, and the cork, in falling, will open the tube. The water thereupon running into the lower reservoir, and from thence into the external vessel, will cause the cork to rise and the flow to cease, and this will occur every time that we remove water from the tazza.” There were, also, vessels which discharged but a certain definite quantity of the liquid that they contained. We have already described one of these, but here is another that is more complicated, wherein the quantity of liquid that it measures out may be caused to vary in the same vessel. A vessel containing wine, and provided with a spout, being placed upon a pedestal, to cause the spout, by the simple moving of a weight, to allow a given quantity of wine to flow; now, for example, half a cotyle (0.13 liter), and now a whole cotyle; or, briefly, any quantity that may be desired. “Let Α Β be the vessel into which the wine is to be put (Fig. 2). Near its bottom there is a spout, Δ. Its neck is closed by a partition, Ε Ζ, through which passes a tube that runs to the bottom, but leaving, however, sufficient space for the passage of the water. Let Κ Λ Μ Ν be the pedestal upon which the vessel stands, and Ξ Ο another tube that reaches as far as the partition and enters the pedestal. In the latter there is sufficient water to stop up the orifice of the tube, Ξ Ο. Finally, let Π Ρ be a lever, half of which is in the interior of the pedestal and the other half external to it, and which pivots on the point Σ, and carries suspended from its extremity, Π, a clepsydra having an aperture, Τ, in the bottom. “The spout being closed, the vessel is filled through the tube, Η Θ, before putting water into the pedestal, so that the air may escape through the tube, Ξ Ο. Then, through any aperture whatever, water is poured into the pedestal in such a way as to close the orifice, Ο; and, after this, the spout, Δ, is opened. It is clear that the wine will not flow, since the air cannot enter anywhere. But, if we depress the extremity, Ρ, of the lever, a part of the clepsydra will rise from the water, and the orifice, Ο, being freed, the spout will flow until the water lifted up in the clepsydra has, on running out, closed this same orifice again. If, when the clepsydra has become full again, we still further depress the extremity, Ρ, the liquid in the clepsydra will take longer to flow out, and more wine will consequently be discharged from the spout. If the clepsydra rises entirely from out the water, the flow will last still longer yet. Instead of depressing the extremity, Ρ, by hand, we may use a weight, Φ, which is movable on the external part of the lever and capable of lifting the whole of the clepsydra out of the water when it is placed near Ρ. This weight, then, will lift a portion only when it is farther away from such point. We must proceed, therefore, with a certain number of experiments upon the flow through the spout, and make notches on the lever arm, Ρ Ξ, and register the quantities of wine that correspond thereto, so that, when we desire to cause a definite quantity to flow, we shall only have to put the weight on the corresponding notch, and leave it.” The miracle of changing water into wine is one of those upon which the ancients exercised their imaginations most. Heron and Philo describe fifteen apparatus designed for effecting this, and more generally for causing different liquors to flow at will from the same vessel. Here is one of the simplest of them (Fig. 3): “There are,” says Heron, “certain drinking-horns which, after wine has been put into them, allow of the flow, when water is introduced into them, now of pure wine, and now of pure water. “They are constructed as follows: Let Α Β Γ Δ be a drinking-horn provided with two diaphragms, Δ Ε and Ζ Η, through which passes a tube, Θ Κ, this being soldered to them and containing an aperture, Λ, slightly above the diaphragm, Ζ Η. Beneath the diaphragm, Δ Ε, there is a vent, Μ, in the side of the vessel. “Such arrangements having been made, if any one, on stopping the orifice, Γ, pours wine into the horn, the liquor will flow through the aperture, Δ, into the compartment, Δ Ε Ζ Η, since the air contained therein can escape through the vent, M. If, now, we close the vent, the wine in the compartment, Δ Ε Ζ Η, will be held there. Consequently, if, on closing the vent, Μ, we pour water into the part, Α Β Δ Ε, of the vessel, pure water will flow out through the orifice, Γ; and if, afterward, we open the vent, Μ, while there is yet water above the upper diaphragm, a mixture of wine and water will flow out. Then, when all the water has been discharged, pure wine will flow. “On opening and closing the vent, Μ, oftener, the nature of the flow may be made to vary; or, what is better still, we may begin by filling the compartment, Δ Ε Ζ Η, with water, and then, closing Μ, pour out the wine from above. Then we shall see a successive flow of pure wine and of wine and water mixed, when we open the vent, Μ, and then, again, of pure wine when the vent is closed anew; and this will occur as many times as we desire it.” [Illustration: FIG. 3.--HERON’S DRINKING-HORN.] The apparatus represented in Fig. 4 is very curious, and might be put to some useful application, without mentioning that which wine merchants might make of it by changing the order of the liquids and leaving in view only the vessel, Α Β, and the cock. “Being given,” says Heron again, “two vessels, one of them containing wine, it is required that whatever be the quantity of water poured into the empty one, the same quantity of a mixture of wine and water, in any proportion whatever (two parts of water to one of wine, for example), shall flow out through a pipe. “Let Α Β be a vessel in the form of a cylinder, or of a rectangular parallelopipedon. At the side of it, and upon the same base, we place another vessel, Γ Δ, which is hermetically closed, and of cylindrical or parallelopipedal form, like Α Β. But the base of Α Β must be double that of Γ Δ if we desire that the quantity of water shall be double that of the wine in the mixture. Near Γ Δ we place another vessel, Ε Ζ, which is likewise closed, and into which we have poured wine. The vessels, Γ Δ and Ε Ζ, are connected by a tube, Η Θ Κ which traverses the diaphragms that close them at their upper part, and which is soldered to these. In the vessel, Ε Ζ, we place a bent siphon, Δ Μ Ν, whose inner leg should come so near to the bottom of the vessel as to leave just enough space for the liquid to pass, while the other leg runs into a neighboring vessel, Ξ Ο. From this latter there starts a tube, Π Ρ, which passes through all the vessels, or the pedestal that supports them, in such a way that it can be easily carried under and very near the bottom of the vessel, Α Β. Another tube, Σ Τ, traverses the partitions in the vessels, Α Β and Γ Δ. Finally, near the bottom of Α Β we adjust a small tube, Υ, which we inclose, with the tube Η Λ, in a pipe, Φ Ξ, that is provided with a key for opening or closing it at will. Into the vessel, Ε Ζ, we pour wine through an aperture, Ω, which we close after the liquor has been introduced. [Illustration: FIG. 4.--AN APPARATUS OF HERON PERMITTING OF MIXING WINE AND WATER IN DEFINITE PROPORTIONS.] “These arrangements having been made, we close the pipe, Ξ Φ and pour water into the vessel, Α Β. A portion, that is to say, one-half, will pass into the vessel, Γ Δ, through the tube, Σ Τ, and the water that enters Γ Δ will drive therefrom a quantity of air equal to itself into Ε Ζ, through the tube, Η Θ Κ. In the same way this air will drive an equal quantity of wine into the vessel, Ο Ξ, through the siphon, Λ Μ Ν. Now, upon opening the pipe, Φ Ξ, the water poured into the vessel, Α Β, and the wine issuing from the vessel, Ο Ξ, through the tube, Π Ρ, will flow together, and this is just what it was proposed to effect.” [Illustration: FIG. 5.--MAGICAL VESSELS OF THE EIGHTEENTH CENTURY.] [Illustration: FIG. 6.--SECTION OF A MAGICAL PITCHER.] The accompanying figures, borrowed from a work on “Scientific Recreations,” by the late editor of _La Nature_, M. Gaston Tissandier, represents a magic vase and pitcher such as the ancients were accustomed to employ for the purpose of practicing a harmless and amusing deception on those who were not acquainted with the structure of the apparatus. For instance, if any one should attempt to pour wine or water from the pitcher shown in the cut, the liquid would run out through the apertures in the sides. But the person who knew how to use the vessel would simply place his finger over the aperture in the hollow handle (Fig. 6) and then suck through the spout, A, when the liquid would flow up through the handle and through a channel running around the rim of the vessel and so reach the spout. These magic vases, cups, pitchers, etc., were not only in use among the ancients, but were quite common in the eighteenth century, and numerous specimens are to be seen in European collections. The ones shown in the accompanying cuts are preserved in the Museum at Sèvres. These apparatus are all based on the use of concealed siphons, or, rather, their construction is based on the principle of that instrument. Devices of this kind admit of very numerous modifications. Thus tankards have been so contrived that the act of applying them to the lips charged the siphon, and the liquid, instead of entering the mouth, then passed through a false passage into a cavity formed for its reception below. By making the cavity of the siphon sufficiently large, a person ignorant of the device would find it a difficult matter even to _taste_ the contents, however thirsty he might be. Dishonest publicans, whose signboards announced “entertainment for man and beast,” are said to have thus despoiled travelers in old times of a portion of their ale or mead, as well as their horses of feed. Oats were put into a perforated manger, and a large part forced through the openings into a receptacle below by the movements of the hungry animal’s mouth. Heron, in the eighth problem of his “_Spiritalia_,” figures and describes a magical pitcher in which a horizontal, minutely perforated partition divides the vessel into two parts. The handle is hollow and air-tight, and at its upper part a small hole is drilled where the thumb or finger can readily cover it. If the lower part of the pitcher be filled with water and the upper with wine, the liquids will not mix as long as the small hole in the handle is closed; the wine can then be either drunk or poured out. If the hole be left open for some time, a mixture of both liquids will be discharged. “With a vessel of this kind,” says an old writer, “you may welcome unbidden guests. Having the lower part already filled with water, call to your servant to fill your pot with wine; then you may drink unto your guest, drinking up all the wine; when he takes the pitcher, thinking to pledge you in the same, and finding the contrary, will happily stay away until he be invited, fearing that his next presumption might more sharply be rewarded.” Another old way of getting rid of an unwelcome visitor was by offering him wine in a cup having double sides and an air-tight cavity formed between them. When the vessel was filled, some of the liquid entered the cavity and compressed the air within, so that when the cup was inclined to the lips and partly emptied, the pressure being diminished, the air expanded and drove part of the contents in the face of the drinker. Another goblet was so contrived that no one could drink out of it unless he understood the art. The liquid was suspended in cavities, and discharged by admitting or excluding air through several secret openings. The apparatus represented in the illustration (Fig. 7) represents an arrangement similar to that of the inexhaustible bottle of Robert-Houdin, but it is more ingenious. The problem proposed, as enunciated by Heron, the Greek engineer, who describes the apparatus, is as follows: “Being given a vessel, to pour into it, through the orifice, wines of several kinds, and to cause any kind that may be designated to flow out through the same orifice, so that, if different persons have poured in different wines, each person may take out in his turn all the wine that belongs to him. “Let Α Β be a hermetically closed vessel whose neck is provided with a diaphragm, Ε Ζ, and which is divided into as many compartments as the kinds of wine that it is proposed to pour into it. Let us suppose, for example, Η Θ and Κ Α are diaphragms forming the three compartments, Μ, Ν, and Ξ, into which wine is to be poured. In the diaphragm, Ε Ζ, there are formed small apertures that correspond respectively to each of the compartments. Let Ο, Π, and Ρ be such apertures, into which are soldered small tubes, Π Σ, Ο Τ, and Ρ Υ, which project into the neck of the vessel. Around each of these tubes there are formed in the diaphragm small apertures like those of a sieve, through which the liquids may flow into the different compartments. When, therefore, it is desired to introduce one of the wines into the vessel, the vents, Σ, Τ, and Υ are stopped with the fingers, and the wine is poured into the neck, Φ, where it will remain without flowing into any of the compartments, because the air contained in the latter has no means of egress. But, if one of the said vents be opened, the air in the compartment corresponding thereto will flow out, and the wine will flow into such compartment through the apertures of the sieve. Then, closing this vent in order to open another, another quantity of wine will be introduced, and so on, whatever be the number of wines and that of the corresponding compartments of the vessel, Α Β. [Illustration: FIG. 7.--THE MAGIC BOTTLE.] “Let us now see how each person in turn can draw his own wine out through the same neck. At the bottom of the vessel, Α Β, there are arranged tubes which start from each of the compartments, to wit: The tube χ ψ from the compartment, Μ; the tube ω σ, from Ν, and the tube λ μ, from Ξ. The extremities, ψ, σ, and μ, of these tubes should communicate with another tube, α, in which is accurately adjusted another, β Γ, closed at Γ at its lower extremity and having apertures to the right of the orifices, ψ, σ, and μ, so that such apertures may, in measure, as the tube revolves, receive respectively the wine contained in each of the compartments and allow it to flow to the exterior through the orifice, β, of the said tube, β Γ. To this tube is fixed an iron rod, δ ε, whose extremity, ε, carries a lead weight, η. To the extremity, δ, is fixed an iron pin supporting a small conical cup whose concavity points upward. Let us therefore suppose this truncated cone established, its wide base at ξ, and its narrow one (through which the pin passes) at θ.[2] Again, one must have small leaden balls of different weights, and in number equal to that of the compartments, Μ, Ν, and Ξ. If the smallest be placed in the cup, ξ θ, it will descend on account of its weight until it applies itself against the internal surface of the cup, and it will be necessary to so arrange things that it may thus cause the tube, β Γ, to turn so as to bring beneath ψ that one of the apertures that corresponds to it, and that will thus receive the wine of the compartment, Μ. This wine will then flow as long as the ball remains in the cup. If, now, the ball be removed, the weight, η, in returning to its first position, will close the orifice, ψ, and stop the flow. If another ball be placed in the cup, a further inclination of the rod, ε δ, will be produced, and the tube, β Γ, will revolve further, so as to bring its corresponding aperture beneath σ. Then the wine contained in the compartment, Ν, will flow. If the ball be removed, the weight, η, will redescend to its primitive place, the aperture, σ, will be closed, and the wine will cease to flow. Finally, upon placing the last ball (which is the heaviest), the tube, β Γ, will turn still more, so as to cause the flow of the wine contained in the compartment, Ξ. [2] The text does not agree with the figure given by the MSS. Moreover, there is an arrangement here that it is difficult to understand from Heron’s description. “It must be remarked that the smallest of the balls should be so heavy that when placed in the cup it shall outweigh the weight, η, and consequently bring about the revolution of the tube, β Γ. The other balls will then be sufficient to cause the revolution of the said tube.” ANCIENT ORGANS. The hydraulic organ filled with its powerful voice the vast arenas in which the gladiators fought, and Petronius relates that Nero one day made a vow to play one of them himself in public if he escaped a danger that threatened him. The invention of them is attributed to Ctesibius. Fig. 1 gives a reproduction of one of these instruments as described by Heron in his “Pneumatics.” [Illustration: FIG. 1.--HYDRAULIC ORGAN.] Let Β Δ be an altar[3] of bronze containing water. Let there be in the latter an inverted hollow hemisphere, Ε Ζ Η (called a damper), that allows the water to pass all around its bottom, and from the top of which rise two tubes that communicate with the interior. One of these tubes, Η Κ, is bent in the interior and communicates with a small inverted box,[4] Ν Η, the aperture of which is at the bottom, and the interior of which is bored out so that it may receive a piston, Ρ Ι, which should fit very accurately so as to allow no air to pass. To this piston is fixed a very strong rod, Τ γ, with which is connected another rod, γ Φ, movable around a pin at γ.[5] This lever moves upon a fixed vertical rod, Ψ Χ. Upon the bottom of the box, Ν Π, is placed another box, Ω, which communicates with the first, and which is closed at the upper part by a cover that contains an aperture to allow of the passage of the air into the box, Ν Π. Under the aperture of this cover, and in order to close it, there is arranged a thin disk, held by means of four pins which pass through apertures in the disk, and are provided with heads in order to hold it in place. This disk is called a platysmatim (Fig. 2). The other tube, Ζ Ζ′, is carried by the hemisphere, Ε Ζ Η, and ends in a transverse tube, Α Α′,[6] upon which rest pipes communicating with it and having at their extremities glossocomiums[7] that communicate with these pipes, and the orifices, Β′, of which are open. Across these orifices, covers provided with holes[8] slide in such a way that when they are pushed toward the interior of the organ their holes correspond to the orifices of the pipes (and to those of the tube Α Α′), and that when they are pulled back, the pipes are closed, since there is no longer any correspondence. [3] Altars were cylindrical or square pedestals, characterized by a cavity in the upper platform, in which a fire was lighted. [4] This box performs here the office of a pump chamber. [5] The figure shows another arrangement. [6] Called a wind-chest in modern organs. [7] Flute mouths. [8] Registers. If, now, the transverse rod, γ Φ, be lowered at Φ the piston, Ρ Σ, will rise and compress the air in the box, Ν Σ Ο Π, and such air will close the aperture of the small box through the intermedium of the platysmatim described above. It will then pass into Ε Ζ Η by means of the tube, Κ Η, then into the transverse tube Α Α′, through the tube Ζ Ζ′, and finally from the transverse tube into the pipes, if the orifices correspond to those of the covers, and this will occur when all the covers (or only a few of them) have been pushed toward the interior. [Illustration: FIGS. 2 AND 3.--DETAILS OF THE HYDRAULIC ORGAN SHOWN IN FIG. 1.] In order that their orifices may be open when it is desired to make certain pipes resound, and that they may be closed when it is desired to cause the sound to cease, the following arrangement is employed: Let us consider isolately one of the mouths placed at the extremity (Fig. 3). Let γ δ be this mouth, δ its orifice, Α Α′ the transverse tube, and σ the cover that is adapted and the aperture of which does not coincide with the apertures of the pipes at this moment. Let us now suppose a jointed arrangement composed of three rods, δ, μ, and ν, the rod, ε δ, being attached to the cover, σ, and the system as a whole moving around a pin, μ. It will be seen that if we lower with the hand the extremity, ν, of the system toward the orifice of the glossocomiums, we shall cause the cover to move toward the interior, and that, when it arrives there, its orifice will coincide with the orifices of the pipes. In order that, upon removing the hand, the cover may be carried back toward the exterior and close all communication, an arrangement such as the following may be employed. Beneath a number of glossocomiums, there is established a bar equal in length to and parallel with the tube, Α Α′, and to which are fixed strong curved plates of horn, such as γ, placed opposite γ δ. A cord is fixed to the end of this plate and winds around the extremity, δ, in such a way that when the cover is moved toward the exterior the cord shall be taut. If the extremity, ν, then be lowered, and the register be thus pushed into the interior, the cord will draw upon the horn plate, and by its force, right it. But as soon as the pressure ceases, the plate will resume its former position and draw the cover back in such a way as to prevent its orifice from establishing a communication. This arrangement being adopted for all the glossocomiums, it will be seen that in order to cause any one of the pipes to resound, it will suffice to depress the corresponding key with the finger. When, on the contrary, it is desired to cause the sound to cease, we shall merely have to lift the finger, and the effect will be produced by the motion of the cover. Water is poured into the small altar in order that the compressed air that is driven from the box, Ν Π, may, owing to the pressure of the liquid, be retained in the damper, Ε Ζ Η, and thus supply the pipes. When the piston, Ρ Σ, is raised, it therefore expels the air from the box into the damper, as has been explained. Then, when it is lowered, it opens the platysmatim of the small box. By this means, the box, Ν Π, becomes filled with air from the exterior, which the piston, raised anew, drives again into the damper. It would be better to render the rod, Τ γ, immovable at Τ, around a pin, and fix at the bottom, Ρ, of the piston a ring through which this pin would pass, so that the piston would have no lateral motion, but would rise and descend with exact perpendicularity. Porta, at the beginning of the seventeenth century, constructed at Naples a hydraulic organ according to the arrangement just described. A few years afterward, in 1645, Father Kircher constructed another at Rome for Pope Innocent X. These organs had the defect of not preserving the note, but of giving a series of harmonies. On the other hand, they produced an exceedingly agreeable tremolo. It was probably these unusual variations in sound that charmed the ears of the Greeks and Romans. Heron afterwards describes a bellows organ, motion to which is communicated not by manual power, but by a windmill. Fig. 4 shows the arrangement with sufficient clearness to permit us to dispense with a description. It is interesting to reproduce, in that it carries the origin of windmills (which it is claimed were unknown to antiquity, because Vitruvius and Varro do not speak of them) back at least to the second century before our era. [Illustration: FIG. 4.--WINDMILL ACTUATING THE BELLOWS OF AN ORGAN.]